pub trait IntoIterator {
type Item;
type IntoIter: Iterator<Item = Self::Item>;
// Required method
fn into_iter(self) -> Self::IntoIter;
}
๐ฌThis is a nightly-only experimental API. (
prelude_2024
)Expand description
Conversion into an Iterator
.
By implementing IntoIterator
for a type, you define how it will be
converted to an iterator. This is common for types which describe a
collection of some kind.
One benefit of implementing IntoIterator
is that your type will work
with Rustโs for
loop syntax.
See also: FromIterator
.
ยงExamples
Basic usage:
let v = [1, 2, 3];
let mut iter = v.into_iter();
assert_eq!(Some(1), iter.next());
assert_eq!(Some(2), iter.next());
assert_eq!(Some(3), iter.next());
assert_eq!(None, iter.next());
Implementing IntoIterator
for your type:
// A sample collection, that's just a wrapper over Vec<T>
#[derive(Debug)]
struct MyCollection(Vec<i32>);
// Let's give it some methods so we can create one and add things
// to it.
impl MyCollection {
fn new() -> MyCollection {
MyCollection(Vec::new())
}
fn add(&mut self, elem: i32) {
self.0.push(elem);
}
}
// and we'll implement IntoIterator
impl IntoIterator for MyCollection {
type Item = i32;
type IntoIter = std::vec::IntoIter<Self::Item>;
fn into_iter(self) -> Self::IntoIter {
self.0.into_iter()
}
}
// Now we can make a new collection...
let mut c = MyCollection::new();
// ... add some stuff to it ...
c.add(0);
c.add(1);
c.add(2);
// ... and then turn it into an Iterator:
for (i, n) in c.into_iter().enumerate() {
assert_eq!(i as i32, n);
}
It is common to use IntoIterator
as a trait bound. This allows
the input collection type to change, so long as it is still an
iterator. Additional bounds can be specified by restricting on
Item
:
fn collect_as_strings<T>(collection: T) -> Vec<String>
where
T: IntoIterator,
T::Item: std::fmt::Debug,
{
collection
.into_iter()
.map(|item| format!("{item:?}"))
.collect()
}
Required Associated Typesยง
Required Methodsยง
sourcefn into_iter(self) -> Self::IntoIter
๐ฌThis is a nightly-only experimental API. (prelude_2024
)
fn into_iter(self) -> Self::IntoIter
prelude_2024
)Creates an iterator from a value.
See the module-level documentation for more.
ยงExamples
let v = [1, 2, 3];
let mut iter = v.into_iter();
assert_eq!(Some(1), iter.next());
assert_eq!(Some(2), iter.next());
assert_eq!(Some(3), iter.next());
assert_eq!(None, iter.next());
Implementorsยง
1.10.0 ยท sourceยงimpl<'a> IntoIterator for &'a UnixListener
impl<'a> IntoIterator for &'a UnixListener
1.6.0 ยท sourceยงimpl<'a> IntoIterator for &'a Path
impl<'a> IntoIterator for &'a Path
1.6.0 ยท sourceยงimpl<'a> IntoIterator for &'a PathBuf
impl<'a> IntoIterator for &'a PathBuf
ยงimpl<'a> IntoIterator for LinkingSectionReader<'a>
impl<'a> IntoIterator for LinkingSectionReader<'a>
ยงimpl<'a> IntoIterator for LocalsReader<'a>
impl<'a> IntoIterator for LocalsReader<'a>
ยงimpl<'a> IntoIterator for OperatorsReader<'a>
impl<'a> IntoIterator for OperatorsReader<'a>
ยงimpl<'a, A> IntoIterator for &'a SmallVec<A>where
A: Array,
impl<'a, A> IntoIterator for &'a SmallVec<A>where
A: Array,
ยงimpl<'a, A> IntoIterator for &'a mut SmallVec<A>where
A: Array,
impl<'a, A> IntoIterator for &'a mut SmallVec<A>where
A: Array,
ยงimpl<'a, K, V> IntoIterator for &'a wasmtime_environ::prelude::IndexMap<K, V>
impl<'a, K, V> IntoIterator for &'a wasmtime_environ::prelude::IndexMap<K, V>
ยงimpl<'a, K, V> IntoIterator for &'a BoxedSlice<K, V>where
K: EntityRef,
impl<'a, K, V> IntoIterator for &'a BoxedSlice<K, V>where
K: EntityRef,
ยงimpl<'a, K, V> IntoIterator for &'a PrimaryMap<K, V>where
K: EntityRef,
impl<'a, K, V> IntoIterator for &'a PrimaryMap<K, V>where
K: EntityRef,
ยงimpl<'a, K, V> IntoIterator for &'a SparseMap<K, V>where
K: EntityRef,
V: SparseMapValue<K>,
impl<'a, K, V> IntoIterator for &'a SparseMap<K, V>where
K: EntityRef,
V: SparseMapValue<K>,
Iterating over the elements of a set.